1. Field of the Invention
The present invention relates to, for example, a transistor and a semiconductor device. The present invention relates to, for example, a method for manufacturing a transistor or a semiconductor device. The present invention relates to, for example, a display device, a light-emitting device, a lighting device, a power storage device, a memory device, a processor, and an electronic device. The present invention relates to a method for manufacturing a display device, a liquid crystal display device, a light-emitting device, a memory device, and an electronic device. The present invention relates to a driving method of a display device, a liquid crystal display device, a light-emitting device, a memory device or an electronic device.
Note that one embodiment of the present invention is not limited to the above technical field. The technical field of one embodiment of the invention disclosed in this specification and the like relates to an object, a method, or a manufacturing method. In addition, one embodiment of the present invention relates to a process, a machine, manufacture, or a composition of matter.
In this specification and the like, a semiconductor device generally means a device that can function by utilizing semiconductor characteristics. A display device, a light-emitting device, a lighting device, an electro-optical device, a semiconductor circuit, and an electronic device include a semiconductor device in some cases.
2. Description of the Related Art
A technique for forming a transistor by using a semiconductor over a substrate having an insulating surface has attracted attention. The transistor is applied to a wide range of semiconductor devices such as an integrated circuit and a display device. Silicon is known as a semiconductor applicable to a transistor.
As a semiconductor for a transistor, different silicon, amorphous silicon and polycrystalline silicon are used depending on the purpose. Amorphous silicon, which can be used to form a film on a large substrate with the established technique, is preferably used for a transistor included in a large display device, for example. In contrast, polycrystalline silicon, which can be used to form a transistor having a high field-effect mobility, is preferably used for a transistor included in a high-performance display device where a driver circuit and a pixel circuit are formed over the same substrate. A known method for forming polycrystalline silicon is to perform high-temperature heat treatment or laser light treatment on amorphous silicon.
In recent years, transistors using oxide semiconductors (typically, In—Ga—Zn oxide) have been actively developed.
Oxide semiconductors have been researched since early times. In 1988, there was a disclosure of a crystal In—Ga—Zn oxide that can be used for a semiconductor element (see Patent Document 1). In 1995, a transistor including an oxide semiconductor was invented, and its electrical characteristics were disclosed (see Patent Document 2).